The first feature you create while building a part is called the base feature; you construct the remainder of the part by adding more features that either modify or add detail to the base feature. This process of building an ABAQUS/CAE native part using the tools in the Part module follows a sequence of operations analogous to building a part in a machine shop. For example, you start with a piece of billet stock (the base feature) and then you do the following:
Attach additional pieces to the billet (apply a solid extrusion, a revolved shell, or a sketched wire).
Cut away the billet (apply an extruded cut, a revolved cut, or a circular hole; or round or chamfer an edge).
When you create a new part, you must describe the base feature. You do this by specifying two properties of the base feature: its shape and type. The shape indicates the basic topology of the feature; that is, whether it is a solid, shell, wire, or point. The type indicates which of the following methods will be used to generate the base feature:
Planar
You sketch the feature on a two-dimensional sketch plane.
Extrusion
You sketch the feature profile and then extrude it through a specified distance.
Revolution
You sketch the feature profile and then revolve it by a specified angle about an axis.
Sweep
You sketch two shapes: a sweep path and a sweep profile. The profile is then swept along the path to create the feature.
Coordinates
You enter the coordinates of a single point in the prompt area.
Table 11–1 shows the base features that you can select based on the part's modeling space and type.
Table 11–1 Choosing the base feature.
| Part Type | Modeling Space | |
|---|---|---|
| Three-dimensional | Two-dimensional or Axisymmetric | |
| Deformable | Any | Planar shell, planar wire, or point |
| Discrete rigid | Any (you must convert a 3-D solid discrete rigid part to a shell before you instance it) | Planar wire or point |
| Analytical rigid | Extruded or revolved shell | Planar wire |
A part imported from a file containing third-party format geometry consists of a single feature that you import into ABAQUS/CAE as the base feature of a new part. You cannot modify this base feature, but you can add additional features to it. Similarly, an orphan mesh part is created in the Mesh module or imported from an output database as the base feature of a new part. You can use the mesh editing tools to add and delete nodes and elements from an orphan mesh part.
